Introduction

The process of manufacture of bitumen emulsion comprises of three basic elements:

  1. a) Bitumen b)         Water              c)         Emulsifiers

By means of applying mechanical shearing energy, the disposition of the bitumen is modified giving place to emulsifier stabilized dispersion on a base of water. This is the most economical way, less contaminating and of less power consumption that exists to apply bitumen on road.

The chemicals that we use for dispersion and stability are called emulsifying agents. These emulsifiers consist of molecules that have two different parts. One is the Lipophilic end with an affinity for asphalt and the other is the Polar end with an affinity for water. Proper distribution of these molecules during manufacture allows the particle surfaces to become electronically charged so that they can repel each other for a long period of time to permit efficient storage and transportation of the product. During this same stage of processing, the emulsion  takes on a cationic or positive charge.

Advantages of Bitumen Emulsion

a) Reduction in Power Consumption as well as labour.

b) Environmental Improvements i.e. Non Polluting, Non-toxic and do not have adverse effect on human beings.

c) Possibility of working with Wet Graded Aggregates.

d) Possibility of exploiting Local materials and

e) Execution of work without any delay.

f) Valuable energy is conserved as no heating is required.

Types of Emulsion

The type of aggregate and climate will define what class of asphalt emulsion should be used – “Cationic” or “Anionic”. In most cases, Anionic Emulsions are limited to use in areas that are basically dry, have limestone aggregates or are used in packaged type of products for long storage life in cans or drums.

Cationic Emulsion represents more than 95% of the entire world market consumption today. The technology for the emulsifier chemistry and type of application equipment make it most logical class of emulsion to use especially today for tropical countries or countries with bad weather conditions.

The Emulsions are sub divided into four sub-groups that depend on their ability to “set” or give off water after being mixed with aggregates when sprayed on surfaces:

  1. Rapid Setting (RS)
  2. Medium Setting (MS) and
  3. Slow Setting (SS)
  4. Polymer modified Bitumen Emulsion for Micro-surfacing

We can normally make any emulsion i.e. Rapid, Medium or Slow Setting By changing the formulation and respective percentages of emulsifiers, Acid, or Asphalt.

Apart from the above, Polymer Modified Emulsions are also being manufactured by us as per IRC SP-81:2008 / Specifications as provided by the client.

Application of Emulsions:

  1. Surface Treatments Aggregates

    1. Prime Coat: This consists of the spray application of an asphalt emulsion on a crushed rock or earth base that we want to make waterproof. The Prime Coat is designed to coat and bond loose mineral particles, to harden or toughen the surface, to waterproof the surface of the base, to plug capillary voids and to provide adhesion between the base and the next course.   Usage of cationic slow setting emulsions that may be fluxed with solvents to induce rapid penetration is recommended.
    2. Tack Coat: A tack coat is a very light spray application of bitumen emulsion . The spray application of an emulsion on top of a surface where you want to place a new asphaltic layer. This layer assures proper adhesion of a new layer to the old surface. Tack coat should not be applied during period of extreme cold or wet whether. Cationic rapid setting emulsions with 60% residual binder content is ideal for tack coat.
    3. Antidust Coating: Spraying a slow setting cationic emulsion diluted with water to improve the roads surface characteristics so that the dust is not produced and surface erosion is eliminated.
    4. Payment Seal Coat: This application is used to seal the top layer of the existing asphalt surfaces from oxidation and water erosion. Rapid setting type of emulsions with less residual binder content must be used.

  2. Surface Treatments with Aggregates

    1. Cold Mix Open Grade Asphalt: For the production of cold mix open graded asphalt, the use of cationic medium setting emulsion with high residual asphalt content should be used. These type of mix is normally used as a maintenance overlay treatment on a road system.
    2. Slurry Seal And Micro-asphalt Concrete: This application is used to resurface, re-seal and retexture an old pavement surface. For roads with a low to medium volume of traffic, slurry seal process with slow setting cationic is ideal. For Roads, Highways and areas with a high traffic volume micro asphalt concrete called MACROSEAL using slow setting polymer modified emulsion is recommended.